It is known to apply heat to glass that is moving through a metal delivery tube by applying a current to the metal delivery tube. During this process, the current density at a certain part of the delivery tube may become disproportionately high and, consequently, the quality of glass may be non-homogeneous or the longevity of the delivery tube may suffer. Thus, there is a need for methods and apparatus for accomplishing a distribution of current density that is more even throughout the delivery tube.